Interactively explores raw profile-mode quantitative LC-MS data with a 2D visualisation similar to Google Maps, but with an asymmetric encoding/decoding scheme specialised to the needs of MS. The LC-MS signal is decomposed into weighted B-spline basis functions that each represent a non-negative baseline component, peak, or peak shoulder. These building blocks are sorted and stored using an R-tree data structure that enables optimised retrieval both spatially and by their overall contribution to the signal. seamass-viz enables the mass spectrometrist to quickly inspect whole runs for ionisation/chromatographic issues, MS/MS precursors for coverage problems, or putative biomarkers for interferences, for example.